Make caller ranking precedence explicit and reproducible

[Widthdom]

Summary

callers --rank-by count can rank a one-reference production caller above a 284-reference test caller because an undocumented source/test preference overrides the requested ranking.

Audit IDs: Q-22. Reproduced with locally built cdidx v1.40.3 at 404db09489c305f17d94f37026e00564d3ac527a.

Existing issue relationship

No exact existing issue was found.

Expected behavior and PR scope

Either count is the true primary key for --rank-by count, or the product exposes an explicit composite ranking mode. Structured query context must state the applied rule/tie-breakers.

Implementation guide for Codex 5.6 sol xhigh

• Represent rank dimensions and precedence explicitly rather than layering hidden post-sort preferences.
• Define stable tie-breakers and deterministic source/test behavior.
• Cover large count differences, ties, include/exclude tests, multiple paths, JSON/human output, and pagination stability.
• Update help/docs with the exact ordering contract.
• Add focused regression/contract tests, run the full net8.0 and net9.0 suite, and add the required bilingual changelog.d/unreleased/ fragment.

Acceptance criteria

• Requested count ranking behaves as documented.
• Query context exposes the active ranking recipe.
• Pages preserve the same deterministic order.

[Widthdom]

Work started on branch fix-issue4881.